Circuit-interrupting means.



I F. E. CASE.

clncun INTERRUPTING MEANS.

APPLICATION FILED JUNE 29, 1914.

Patented May 22, 1917.

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M MJ vUNITED sTATEs PATENT oEEioE.

vFRANK E. CASE, F SCHENECTADY, NEW YORK, ASsIGNoR To GENERAL ELECTRIC COMPANY, A CORPDRATION OENEW YORK.

CIBCUIT-INTERRUPTING MEANS.

Specification of Letters Patent.

Patented May 22, 1917.

Application filed June 29, 1914. Serial No. 847,892.

frupting Means, of which the following is a specification.

i tainable through my invention I may men-4 .tion adaptability of interrupting means em- L,My invention relates to electric circuit interrupting means, and it is particularly con- 'cerned with the mounting and inclosure of such means. Among the advantages obbodying it to relatively high voltages and heavy currents, avoidance of electrical creepH -.age, and structural simplicity and compactness. The invention is especially applicable to circuit interrupting devices in which provlsion is made for detiectmg and extinguishing any are that may arise when the circuit .is opened,-such as blow-out circuit breakers andcontactors and blow-out fuses wherein k by the current.

opening of a circuit under conditions of eX- cessive current low is brought about by overheating of a fusible conductor traversed The invention can best be presentedby the description of a particular structure, and I have accordingly illustrated and described in detail a magnetic blow-out fuse suitable for use on electric locomotives that is the best embodiment at present known to me. IVhile, however. the invention extends to various special features and details and combinations and arrangements of parts herein set forth, it is not confined thereto, but can be otherwise carried out and applied.

In the accompanying drawing, Figure 1 Ais a vertical section through the inclosing structure of the apparatus.

Fig, 2 is a corresponding horizontal section taken on a plane indicated by the line 2-2 in Fig. 1.

The principal parts of the apparatus are inclosed in an' insulating casing 1 that is in eect a shallow box turned on edge and open at its lower side. The terminals 2, 3 between which extends the replaceable fuse conductor (a strip of sheet copper with a hole in its middle, for example) are shown as clamps having movable Wedge-like jaw pieces t, 4 operated by screws with handles for turning them. The upper fixed portions of these terminal clamps 2, 3 lhave arcing tips 5, 5

intended to prevent or minimize injury to the clamps by any arc that may form when the fuse conductor is ruptured. As shown, the magnetic field for taking care of the arc is produced electrically by means comprising coils G, 7 associated with the terminals 2, 3 and connected in series with them and with one another between the main current leads 8, 9. The action of the coils 6 7, is made more effective by -means of pole pieces 10, 10 and 11. l1 associated in pairs with the respective terminals 2, 3 and so arranged that under the influence of the coils those of each pair will del-lect downward between them and so break any arc that may form. The coils (3, 7 may be of heavy flattened copper wire or may be formed by helical cutting of a. hollow copper cylinder, and the pole pieces 10, 10 and 11, 11 for said coils 6, 7 may be pressed or stamped from soft sheet iron.

The terminals 2, 3 and associated parts are supported and more or less inc losed by separate insulating means including walls 12 of refractory insulating material arranged in pairs between the pole pieces 10, 10 and 11, 11 respectively in such a way that in the region where the arc may be the material is nowhere continuous, so that there is only a very circuitous, roundabout path for electrical creepage between the terminals and between their respect-ive current connections 6, S and 7, 9, etc. To this end, not only are the walls 12 of each pair separated So as to afford space for the deflection of the arc and serve as protective linings for the pole pieces, but the pairs of walls are themselves separated so that they form individual arcchutes for the terminals 2, 3 that are separated by an intervening air-space at 13. The lower portions of these chutes are themselves further closed and separated by transverse vertical walls 14. 14: extending between the adjacent edges of the walls 12. Additional protection is afforded by additional walls 15 arranged very much like the walls 12, but entirely outside of the pole-pieces 10` 10 and 11I` 11 respectively and extending clear up to the top of the casing 1 at the rear and to about the same height as said walls 12 in front. Thus each pole piece is in eifect contained in a single hollow wall formed by the walls 12 and 15 at that side of the corresponding arc chute. Horizontal and vertical insulating strips 16 and 17 secured between such walls 12 and 15 at the upper edges of the former and at the edges of both adjacent the air space 13 render the inclosure of the pole pieces more complete. Transverse ver.

tical walls 18, 18 analogous to the walls 14, 14 extend forward from the rear walls 15 to the front of the casing 1.

A number of vertical strips 19 arranged between the walls 15 and the front and rear walls of the casing '1 serve principally for spacing the latterfrom the former and as an aid in securing them in the casing. The rear walls 15 have openings for the current leads 8, 9, and the rear wall of the casing has corresponding holes in which are insulating sleeves 2O that surround and protect said leads. The rear wall of the casing 1 has projecting end portions with holes 21 for securing means for mounting the apparatus on any suitable insulating support, which should preferably be grounded. Beneath the lower ends of the arc chutes may be mounted a baille 22 inclined forward and' downward so as to direct the conductive gases from'the arc away from any adjacent structure. It is to be understood, however, that the apparatus is shown with tle arc chutes directed downward merely for convenience of illustration, since in practice it will often be preferred to direct them diagonally 'or directly upward in order that the tendency of the heated gases to rise may aid in extinguishing the arc. While the various walls may be made of anyl materials of suitable insulating and refractory properti-es, the material disclosed in United States Patent No. A1,009,630 to L. E. Barringer granted Nov. 21, 1911 is very suitable f and advantageous for the purpose.

As indicating the advantages of my in' vention as regards compactness, I may mention that an apparatus in which the casing 1 is about two feet long and other parts in the relative proportions shown will operate satisfactorily for voltages as high as 2400 or 'higher with direct currents of from 200 to 1000 amper-es or more.

i What I claim as new and desire to secure y by Letters Patent of the United States, is :-n

1. The combination ofterminals for an electric fuse conductor, means for deflecting and breaking any arc formed when the fuse conductor is ruptured, and separate insulating means inclosingand supporting the respective terminals and affording only a circuitous creepage path between them and between their respective current connec tions.

2. The combination of terminals, means for defiecting and breaking any arc formed between them, and insulating means `inclosing the respective terminals and forming for them individual arc chutes separated atl their adjacent sides so lthat in the region. of the are the insulating material is nowhere continuous between them.

3. The combination of terminals, electromagnetic means for deflecting and breaking any arc from them, and insulating means inf closing the respective terminals and forming for them individual arc-chutes separated by an intervening air space.

ll. The combination of terminals, electromagnetic blowout coil means associated with said terminals, pole piece means for said coil means arranged to deflect and break any arc from said terminals, and a pair of refractory insulating walls associated with each terminal and forming for it an arc chute, the walls of each pair being so separated from those of the other pair that only a circuitous creepage path exists between the chutes.

5. The combination of terminals, electromagnetic blowout coils associated with said terminals, pole pieces for said coils associated in pairs with the respective terminals and arranged to deflect and break between them any arc from said terminals, refractory insulating walls arranged in pairs between the pole pieces of each pair and forming individual are chutes for the terminals, the walls of the respective pairs being so separated that the two pairs forming separate arc-chutes for the respective terminals, apit insulating means forming an inclosing casing for the parts aforesaid.

In witness whereof, I have hereunto set my hand this 26th day of June, 1914.

FRANK E. CASE.

llVitnesses:

BENJAMIN B. HULL, MARGARET E. WOOLLEY. 

